Single Transformer - Hitachi RET670 Commissioning Manual

1MRK 504 165-UEN Rev. K
This condition may cause an alarm or total block of the voltage control function to be displayed
on the local HMI.
3. Inject a current higher than the Iblock setting and confirm the alarm or blocking condition is
present on the local HMI. If an automatic or total blocking condition occurs, change the applied
secondary voltage and confirm that no tap change commands are issued from the associated
binary outputs. This situation can also be confirmed through reviewing the disturbance and
service reports on the local HMI.
11.11.5.7

Single transformer

Load drop compensation
1. Confirm that OperationLDC is set to On.
2. Confirm settings for Rline and Xline.
3. Calculate the expected load voltage U
based on secondary injection of transformer secondary voltage (U
current (I
EQUATION2080 V3 EN-US
where:
U
When all secondary phase-to-earth voltages are available, use the positive-sequence
components of voltage and current. By separation of real and imaginary parts:
ul re ub re rline il re
EQUATION2082 V1 EN-US
ul im ub im
EQUATION2084 V1 EN-US
where:
ub
il
rline
xline
For comparison with the set-point value, the modulus of U
¦ U
EQUATION2086 V2 EN-US
4. Inject voltage for U
5. Inject current equal to rated current I2Base.
6. Confirm on the local HMI that service values for bus voltage and load current are equal to
injected quantities.
7. Confirm that the calculated value for load voltage, displayed on the local HMI, is equal to that
derived through hand calculations.
Transformer protection RET670
Commissioning manual
= I1Base), in accordance with equation 121.
L
, I = Re(I ) + jlm(I ) are complex phase quantities
L L L L
= - × +
, , , xline il im
= - × -
, , xline il re rline il im ,
is the complex value of the busbar voltage
is the complex value of the line current (secondary side)
is the value of the line resistance
is the value of the line reactance
2 2
¦ = (ul , re) + (ul , im)
L
equal to setting USet.
B
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(displayed as a measured value on the local HMI)
L
×
,
×
,
Testing functionality by secondary injection
= USet) and rated load
B
are according to equation 124.
L
Section 11
SEMOD175185-669 v2
SEMOD175185-672 v5
(Equation 121)
(Equation 122)
(Equation 123)
(Equation 124)
245